Histone synthesis and differentiation in murine virus-infected erythroleukemia cells

The murine virus-infected erythroleukemia cells (MELC) has been used as a useful tool to examine the regulatory mechanism of the cytodifferentiation by the genetic approach. Addition of dimethylsulfoxide (DMSO) to the MELC culture induces erythroid differentiation. A study was made to assess whether stimulation of histone synthesis is associated with DMSO-induced differentiation of MELC during 4 days of culture in vitro. The synthesis of histone increased 2-fold in the 48 hr-incubated cells while the synthesis of non-histone protein was not stimulated. The histone synthesis was maximal at 48 hr and declined by 72 hr. 3H-leucine-labeled cells treated with DMSO was mixed with an equal weight of 14C-labeled control cells. Histones were isolated and fractionated on polyacrylamide gel. A 3.6-fold increase in 3H/14C ratio occurred in histone fraction 3 and 3.4-fold in histone fraction 2b. The data indicate that the stimulation of histone synthesis is an early event following DMSO treatment of MELC cells.